This invention relates to an electrical junction box for a motor vehicle and more particularly relates to the junction box that can prevent breakage of a terminal of a fusible link and a link body when the fusible link is secured by a bolt to a bus bar accommodated in a casing of the electrical junction box.
For convenience of explanation, a conventional electrical junction box for a motor vehicle will be described by referring to FIGS. 11A, 11B, and 12. FIG. 11A is a plan view of a conventional electrical junction box. FIG. 11B is a longitudinal section view of the junction box taken along line I2—I2 in FIG. 11A. FIG. 12 is a plan view of another conventional fusible link.
The present applicant has previously proposed an electrical junction box 1 shown in FIGS. 11A and 11B. Patent Public Disclosure No. HEI 10-174254 (1998) discloses the electrical junction box 1 in which terminals of a fusible link are secured by a bolt to bus bars made of a conductive metal plate in a casing. The electrical junction box 1 has a casing including an upper casing member 2 and a lower casing member 3. The casing accommodates an assembly in which a plurality of bus bars 4 and insulation plates 5 are piled on one after another. An end of the bus bar 4 extends to a lower part of a fusible link containing-section 2a provided on the upper casing member 2. The extending end of the bus bar 4 is provided on a given position with a bolt hole (not shown). On the other hand, a fusible link 6 to be accommodated in the fusible link containing-section 2a is provided on the opposite sides of a link body 7 with an input terminal 8 and an output terminal 9 having bolt holes (not shown), respectively. When the fusible link 6 is accommodated in the fusible link containing-section 2a, the bolt holes in the bus bars 4 and the bolt holes in the input and output terminals of the fusible link 6 are aligned coaxially with one another and joined by bolts B.
However, there is a problem that heat radiation of the bus bars is lowered in the above structure, since the link body of the fusible link 6 and the input and output terminals 8 and 9 cover the whole upper surface of the bus bars 4.
Accordingly, as shown in FIG. 12, a structure is proposed in which the fusible link containing-section 2a is enlarged and the bus bars 4 to be connected to the input and output terminals 8 and 9 of the fusible link 6 are exposed to enhance heat radiation.
However, in this structure, when the bolts B fasten the input and output terminals 8 and 9 of the fusible link 6 onto the bus bars 4, a turning force of the bolt B moves the input terminal 8 or the output terminal 9 in the turning direction of the bolt B, since the input and output terminals 8 and 9 of the fusible link 6 are not fixed in the turning direction. This may break joining parts between the link body 7 and the input and output terminals 8 and 9.
In view of the above problems, an object of the present invention is to provide an electrical junction box for a motor vehicle that can prevent degradation of heat radiation of bus bars connected to terminals of a fusible link and can prevent breakage of the terminals of the fusible link and a link body when fastening by bolts.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.